Lady Gaga has been taken to hospital suffering from "severe physical pain".
The singer has cancelled a performance at Rock In Rio in Brazil as a result.
A statement on her Instagram page said: "Lady Gaga is suffering from severe physical pain that has impacted her ability to perform.
"As a result, she sadly must withdraw from this Friday's Rock In Rio performance.
"Lady Gaga is under the care of expert medical professionals.
"She sends her love to all her fans in Rio and thanks them for their support and understanding."
The singer also posted a picture of her arm with a drip in it, captioned: "Brazil, I'm devastated that I'm not well enough to come to Rock In Rio.
"I would do anything 4 u but I have to take care of my body right now. I ask for your grace and understanding, and promise that I will come back and perform for you soon. I'm so sorry, and I love you so much."
She also posted a close-up picture of a tattoo reading Rio on the back of her neck captioned: "I was taken to the hospital, it is not simply hip pain or wear and tear from the road, I am in severe pain.
"But am in good hands w/ the very best doctors. Please don't forget my love for you.
"Remember years ago when I tattooed Rio on my neck, the tattoo was written by children in the favelas. Rio. You hold a special place in my heart I love you."
Earlier this month she cancelled a show in Montreal after falling ill during another concert.
The singer said she was "devastated" to miss the gig on September 4 and attributed her illness to singing in the rain during a show in New York.
She was recently at the Toronto International Film Festival promoting her Netflix documentary Gaga: Five Foot Two.
The UK leg of her world tour is scheduled to begin in London on October 9 before moving to Birmingham and Manchester.